The formation features of supercritical steam-water jets (review)

Abstract

The review of works on study of dynamics formation of water fluid jet of supercritical parameters outflowing from a high-pressure chamber through a thin nozzle has been carried out. The system of model equations describing the dynamics of outflow processes in both single-phase and multiphase gas-vapor-liquid media is considered. It based on the laws of conservation of mass, momentum and energy of phases in accordance with single-pressure, single-speed and two-temperature approximations with the allowance for contact-type heat transfer and mass transfer for evaporation and condensation under equilibrium conditions. The numerical realization of model representations is carried out by the method of movable Lagrangian grids and using modified solvers of the OpenFOAM package. The analysis of the features initial stage of the formation of a steam-water jet at outflow through a thin nozzle is given based on the results of numerical simulation by the Lagrangian method in the case of a two-dimensional axisymmetric formulation. The problems about the study of the evolution a forming jet during the outflow of a single-phase flow of water-steam and a boiling jet of supercritical state parameters are considered, by the numerical realization in the OpenFOAM package. The features the formation of Mach disk, accompanied by the appearance of a cavity inside the jet, are noted. It is shown that during the outflow of a boiling steam-water jet, the vortex zones are formed near the axis of symmetry and periodic pulsations of pressure and mass velocity are generated, which subsequently lead to acoustic oscillations preceding the main jet flow observed in experiments. The justification of reliability the applied numerical method realized by the new OpenFOAM solvers is given on the example of comparing numerical and analytical solutions to L.I. Sedov’s problem of a point explosion in two-phase gas-drop mixture and comparing the results of numerical solution and experimental photography of supersonic nitrogen jet outflowing through cylindrical nozzle from high-pressure vessel.